Jan. 21, 2010 -- Soaking in more sunlight and drinking more dairy may help
you ward off colon cancer.

Researchers in Europe have found that people with abundant levels of vitamin
D -- the so-called sunshine vitamin -- have a much lower risk of colon cancer.
The findings add to a growing body of evidence that suggest vitamin D may have
the power to help prevent colon cancer and possibly even improve survival in
those who have the disease.

The body makes vitamin D after the skin absorbs some of the sun's rays. You
can also get vitamin D by consuming certain foods and beverages, such as milk
and cereal, which have been fortified with the vitamin, but few foods naturally
contain it.

For the current study, researchers looked at the link between blood levels
of vitamin D as well as dietary vitamin D and calcium, and who was at risk for
colorectal cancer. They based their findings on information from the European
Prospective Investigation into Cancer Study (EPIC), a study of more
than 520,000 people from 10 Western European countries. The study
participants gave blood samples and completed detailed diet and lifestyle
questionnaires between 1992 and 1998.

During the follow-up period, 1,248 patients were diagnosed with colorectal
cancer. Researchers compared their lifestyle and diet backgrounds to the same
number of healthy patients. They discovered that those with the highest blood
levels of vitamin D had a nearly 40% decrease in colorectal cancer risk than
those with the lowest levels.

However, the best way to boost your vitamin D level may be a matter of
debate. As vitamin D's potential health benefits become more widely advertised,
more people may advocate supplementation. However, the researchers say it's
unclear if supplements are better at increasing blood levels of vitamin D than
a balanced diet and moderate exposure to outdoor sunlight. They caution that
the long-term effects of taking large doses of vitamin D supplements have not
been well studied.

"Our findings suggest that the potential cancer risk benefits of higher
vitamin D levels should be balanced with caution for the toxic potential," they
write in today's online version of BMJ. "Before any public health
recommendations can be made for vitamin D supplementation, new randomized
trials are needed to test the hypothesis that increases in [blood levels of
vitamin D] are effective in reducing colorectal cancer risk without inducing
serious adverse events."

Colorectal cancer is the third most common cancer in men and women in the
U.S., according to the American Cancer Society.

SOURCES: News release, BMJ.

Jenab, M. BMJ, Jan. 20, 2010; vol 340.

American Cancer Society web site: "How Many People Get Colorectal Cancer."